Trackway apparatus for automatic train control



TRACKWAY APPARATUS FOR AUTOMATIC TRAIN CONTROL Filed July 24. 1940' a0 p 49 vdyu mm w 51 mw 1 E Z cm H4 I: "WW .c c a u m m B m Lc 4------9 up B B HIS ATTORNEY Patented Mar. 10, 1942 TRACKVVAY APPARATUS FOR AUTOMATIC TRAIN CONTROL Ralph R. Kernmerer, Swissvale, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pin, a corporation of Pennsylvania Application July 24, 1940, Serial No. 347,243

8 Claims.

My invention relates to trackway apparatus for automatic train control and more particularly to apparatus of this character which provides means for testing the train-carried equipment on a moving train for operativeness prior to the entry of such a train into automatic train control territory.

One object of my invention is to provide apparatus of the above character which enables the necessary tests to be made at speed and in such a manner as to require a minimum reduction in the train speed and negligible loss of time while the tests are being made. Another object of my invention is to provide control of the signal which governs the entrance to the test section in such a manner that entry of a train will not be permitted unless the code apparatus associated with the test section is functioning properly. A further object of my invention is to establish certain test operations which occur automatically and in proper sequence upon the entry of a train into the test section. A still further object of my invention is to provide an indication that the trackway apparatus has properly cycled through the test routine, thus apprising the engineman that the fault, if any, is in the train-carried apparatus.

I accomplish the foregoing objects by establishing definite sequential time intervals during some of which certain characteristic codes are applied to the trackway, these time intervals providing an opportunity for certain action to be taken by the engineman for the purpose of ascertaining that the train-carried equipment is in proper working order.

I shall describe one form of apparatus embodying my invention and shall then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing a section of test track equipped with apparatus embodying my invention.

In the operation of trains equipped with automatic train control it is customary to make a certain series of tests known as a departure test at terminal points or in yards where the trains are made up. Since this test is made with the locomotive at standstill, it does not bring into play all features of the automatic train control. The apparatus embodying my invention is not intended to do away with the regular departure test but is intended to supplement this test so that inoperative irregularities which would not show up at standstill will be detected and removed before the train. is authorized toproceed into automatic train control territory.. The running test required by apparatus embodying my invention provides an automatic means of enforcing a predetermined routine in making a brief and simple test of the performance of the train control equipment, just prior to a movement into automatic train control territory. The section of test track should preferably be so located and arranged as to permit inoperative car equipment to be readily detached and replaced by an operative unit when a failure is detected.

Referring to the drawing, the section DE is the test section in which the running test of the train control apparatus is made, the trafiic direction being normally from left to right, as indicated by the arrow. If this section is in electrified territory, then the impedance bonds IB shown diagrammatically at each end of the section will be required. At one end of the section is the track transformer T which normally supplies coded alternating current to the rails of the section through a current-limiting resistor R. At the other end of the section is the usual code following track relay TR which, as shown herein, is of the direct current type and is energized from the rails through the usual transformerrectifier unit TRU shown diagrammatically for purposes of simplicity.

Relay TR follows the code supplied by transformer T and in so doing reversibly energizes the input winding of the decoding transformer DT from a source of direct current having the terminals BC, over its contacts l2 and l-3. The protective condenser PC reduces the sparking at these contacts. The resulting output from .the transformer DT is rectified over a second contact finger 4 of relay TR. and this output maintains the decoding relay DR normally energized as long as relay TR continues to follow code. Thus, relay DR checks the code following action of relay TR. The snubbing resistor SR. reduces the tendency of relay DR to pulse on the rectified output of the decoding transformer and. reduces sparking at contact finger 4. well known so that the operation of this portion of the apparatus need not be described in further detail.

When the section DE is unoccupied, as shown in the drawing, alternating current which is coded at the rate of 75 times per minute will be supplied to the rails by virtue of the operation of the constantly energized code transmitter CT'l5 and the code supply circuit which may be traced as follows: from one terminal BX of a source of alternating current, wire 5, periodically operat- All of the apparatus so far described is ing contact 5 of the code transmitter CT'I5, wires 7 and 8, front contact 9 of relay DR, and wire I0, to the input winding of transformer T and the other terminal CX of the source. Relay TR will therefore be following 75 code and relay DR will be picked up so that under the unoccupied condition the track circuit will behave in the same sarily critical in their significance but are used I mainly for convenience. Relay DR'I'P is a repeater of relays DR and DRP. The functions of all of these relays will become clear as the description progresses.

Relay DRP is normally energized over a circuit which includes the front contact I I of relay DR, wire I2, back contacts I3, I4 and I5 of relays DRPS, CIR and COR, respectively, and wire I6. When relays DR and DRP are both up, repeater relay DRTP is picked up over a circuit which includes front contact I! of relay DR, wire I8, front contact I9 of relay DRP, and wire 20. The pick-up of relay DRTP closes a control circuit for the entering signal S at location D, over front contact 2| and wire 22. This control circuit is not shown completely as it will ordinarily include additional apparatus forming no part of my present invention but it will be understood that the closure of front cont-act 2i permits clearing of signal S to be effected, whereby a train will not be authorized to enter the section D-E unless the coding apparatus of the section is in proper operating condition as evidenced by the picked up condition of relays DR, DRP and DRTP. This avoids the testing of locomotive apparatus and possible rejection and substitution of another car, only to find that the defect existed not in the car-carried apparatus but in the wayside equipment.

An additional indication of the proper condition of the wayside equipment can be provided by a lamp L or other suitable indicator on the track model in the dispatchers oflice, this lamp being energized over a front contact 23 of the relay DRTP.

I shall next provide a general description of the means which I employ for automatically enforcing a definite test routine, before the specific apparatus and circuits are described in detail. The tests consist of three main steps, each consuming about 5 seconds so that the total running test period is about seconds. During the first 5 second interval following the entry of a train into the test section, 75 code is applied to the section, followed in turn by a 5 second period of no code, and a period of 240 code. The period of 240 code will usually have a minimum duration of 5 seconds, also, although it may be longer, depending on how long the section remains occupied. After the train has accepted the wayside signal and has entered the test track circuit, the 5 seconds of 75 code will cause the train-carried equipment to cut in, with the display of a proper (caution) cab signal indication, provided that the train speed does not then exceed more than about 1'7 miles per hour. Should the train speed be in excess of this value, then after the equipment cuts in, the speed whistle will sound and the engineman must take proper action to suppress the brake application which would automatically follow in the absence of such forestalling action on his part.

At the expiration of the 5 second period of code, a 5 second period of no code will follow. Absence of code in the track will cause a danger cab signal to appear which will require acknowledgement by the engineman in order that the train may proceed. If the speed is above about 11 miles per hour, then an automatic brake application will occur unless this is suppressed by the engineman. At the expiration of the 5 second no code period, a period of 240 code will be effective for cutting out the equipment. Thereafter, the speed restrictions are lifted so that the brakes, if applied, may be released and the train continue at speed.

Assuming now that the train has just entered the section D-E, the first time cycle to be measured is the 5 second period of 75 code. The deenergization of relay TR will cause relay DR to release, whereupon the previously traced energizing circuit for timing relay DRP will be interrupted at the front contact Ii of relay DR. Relay DR'IP will release due to the opening of front contact I! of relay DR so that the signal S cannot now be cleared for a following train, and the indicator L will indicate occupancy of the section. After about 2.5 seconds, relay DRP will release, closing a pick-up circuit for the second timing relay DRPS which circuit includes the following: back point of contact I I of relay DR, wire 24, back contact 25 of relay COR, wire 26, back contact 27 of relay CIR, wire 28, back contact 29 of relay DRP, and wire 35).

Relay DRPS will pick up after a 2.5 second interval and in so doing will close a stick circuit for itself which includes back contact 27 of relay CIR and which may be traced from wire 26 of the pickup circuit over wire 3|, front contact 32 of relay DRPS, Wire 33, back contact 29 of relay DRP, and wire 38. The purpose of this stick circuit is to retain relay DRPS energized after the cut-in relay CIR picks up.

It will be noted that up to this point, a 5 second interval following the entry of the train into the test section has been accurately measured by adding the 2.5 second release interval of timing relay DRP to the 2.5 second pick-up'interval of timing relay DRPS. By employing the pick-up interval of one relay and the release interval of the other, rather than tWo pick-up intervals or two release intervals, I provide close regulation of the time cycle since this cycle becomes substantially independent of ordinary voltage and temperature variations. Obviously, however, this particular arrangement is not essential for carrying out the purposes of my invention.

The release of the decoding relay DR when the train enters the section transfers the supply of 75 code from the front point of contact 9 of relay DR, as previously traced, to the back point of this contact so that the 75 code or cut-in code is now supplied over the following circuit: terminal BX, wire 5, contact 6 of the coder, wires 1 and 34, back contacts 35 and 36 of relays CIR and COR, respectively, wire 31, back point of contact 9, and wire II], to the track transformer T.

As soon as relay DRPS picks up, a pick-up circuit is closed for the cut-in relay CIR which immediately picks up and in so doing cuts oil the '75 code at its contact 35 and initiates the second period of no code; The pick-up circuit for relay CIR may be traced from the back point of contact ll of relay DR, wires 2t and 38, front contact 3% of relay DRPS, wire tit, back contact 4| of relay DRP, wire 42, back contact d3 of relay COR, and wires tit and 5,8, to the relay winding. The pick-up of relay CIR closes a stick circuit for this relay which may be traced from the back point of contact ll of relay DR, wire 2d, back contact of relay COR, wire 26, front contact 2'! of relay CIR, and wires and 26, to the relay winding. As pointed out before, the pick-up of relay CIR causes code to be cut off the test section for a period of 5 seconds, and exit of the train from the section within this interval will not restore the code until after this period has expired.

When cut-in relay CIR picks up, a second pickup circuit is closed for the timing relay DRP which may be traced as follows: from back contact ll of relay DR, wires 24 and 33, front contact 39 of relay DRPS, wires it and il, front contact hi of relay CIR, back contact lb of relay COR, and wire it. After 2.5 seconds, relay DRP will pick up and in so doing will open the energizing circuit for the second timing relay DRPS at its back contact 29 so that after a further period of 2.5 seconds, relay DRPS will release. The pick-up of relay DRI and subsequent release of relay DRPS together establish the 5 second no code interval during which, as previously pointed out, the engineman must take certain action in order to proceed.

Relay DRPS, in releasing, causes the release of relay DRP through opening of front contact 3d and closes a pick-up circuit for the cut-out relay COR. This circuit may be traced from back contact H of relay DR, wires 2d and 38, back contact 39 of relay DRPS, wire t3, front contact 49 of relay DRP, wire til, front contact 5! of relay CIR, and wires 52 and 53:, to relay COR. A stick circuit now becomes closed for relay COR over back contact H of relay DR, wire t l, front contact 25 of relay COR, and wire 53. It will be noted that the energized condition of relay COR now depends only on the released condition of relay DR but not on any of the remaining relays, so that relay COR will remain energized as long as the track circuit continues to be occupied.

When relay COR picks up, it applies the 24-1) code or cut-out code to the test section over a circuit which may be traced as follows: from the terminal BX, wire 5, contact 543 of coder CTZMI, wire '55, front contact 38 of relay COR, wire 37, back contact 9 of relay DR, wire 99, and winding of track transformer T, to the other terminal CX of the alternating current source. Coder CT24il will be operating because its operation will have started when the train first entered the section due to the closing of an energizing circuit for the coder over back contact I! of relay DR. As pointed out before, the 240 code permits cutting out of the train control equipment aboard the train.

Pick-up of relay COR will open the stick circuit for relay CIR at the back point of contact 25 so that the latter relay will release. Accordingly, all of the relays except COR will now be deenergized. The pick-up of relay COR will also energize a wayside test indicator TI over its front contact 56 to provide an indication that the wayside apparatus has properly cycled through its test routine,

After the test is completed and the train leaves these'ction, all of the apparatus will be automatic'all'y restored to the condition in which it is shown. This is accomplished as follows. When the track circuit is vacated, the first code cycle of 240 code will operate the code following track relay TR so that the decoding relay DR will pick up, opening the stick circuit for relay COR at its back contact It so that relay COR will release and in so doing will restore the pick-up circuit originally traced for relay DRP. Also,

'75 code will be restored to the track circuit over front contact 9 of relay DR. At the expiration of the 2.5 second interval for relay DRP, this relay will pick up, energizing relay DRTP and the indicator L whereupon the signal S may be cleared for another train movement into the section.

From the foregoing description it will be apparent that I have provided trackway apparatus which automatically enforces a predetermined test routine aboard a train while such train is passing over the test section, with a minimum loss of time to the train, and which provides proper indications to show that the test apparatus itself is in proper working order so that a defect, if any, may be localized in the traincarried apparatus.

The particular codes which I haveused, their sequence, and the duration of each code or time interval are obviously capable of wide modificatioh to suit particular operating conditions and equipment. The same code can be used throughout if the test section adjoins train control territory or if automatic cut-out is not essential. If desired, the number of characteristic test intervals can be either decreased or increased, depending upon the number and type of function which it is necessary to test aboard the train. This can be accomplished either by rearranging the timing and control relays or introducing an additional relay to provide another step in the sequence of test operations. Such modifications will be obvious to those familiar with railway signaling and automatic train control.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that, various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. The method of making a test of automatic train control equipment at speed which comprises, establishing a first time interval during which cut-in code is supplied to the train for cutting in the train control equipment and providing a cab signal indication that code is being received, establishing a second time interval of no code for enforcing acknowledgment and brake suppression, and establishing a third time interval during which a second code is supplied to the train for cutting out said train control equipment and lifting speed restrictions, said three time intervals following one another automatically and in proper sequence once the train passes a given point in the trackway.

2. In combination with a section of railway track, means for normally supplying the rails of said section with coded current, means automatically effective upon entry of a train into said section for establishing a first predetermined time interval during which said coded current continues to be supplied to said section followed by a second predetermined time interval during which the supply of code is discontinued, said predetermined intervals providing a means of testing the operativeness of the car-carried train control equipment, and means effective at the expiration of said two time intervals for again supplying coded current to said section for cutting out said train control equipment.

3. In combination with a section of railway track, means for normally supplying the rails of said section with coded current, an entering signal for said section, control means for said signal responsive to the presence of said coded current in said section to prevent entry of a train if said coded current is absent, means automatically efiective upon the entry of a train into said section for establishing a first predetermined time interval during which said coded current continues to be supplied to said section followed by a second predetermined time interval during which the supply of code is discontinued, said predetermined intervals providing a means of testing the operativeness of the car-carried train control equipment, and means effective at the expiration of said two time intervals for again supplying coded current to said section for cutting out said train control equipment.

4. In combination with a section of railway track, means for normally supplying the rails of said section with current coded at a first rate,

means automatically effective upon the entry of a train into said section for establishing a, first time interval during which current coded at said first rate is supplied to said section followed by a second time interval during which the supply of code is discontinued, said time intervals providing a means of testing the operativeness of the car-carried train control equipment, and means effective at the expiration of said two time intervals for supplying current coded at a second rate to said section for cutting out said train control equipment.

5. In combination with a test section of railway track, means for normally supplying the rails of said section with coded current, a pair of timing relays, means effective when a train enters said section for causing operation of said two relays in sequence whereby the operating times thereof are added to provide a first predetermined time interval for testing the train control equipment of said train on said coded current, means controlled by the operation of the second of said timing relays for cutting olf said code for a second predetermined time interval for testing the safety features of said train control equipment, and other means controlled by said timing relays effective at the expiration of said second time interval for reapplying code to said section to thereby enable said train control equipment to be cut out.

6. In combination with a test section of railway track, means for normally supplying the rails of said section with coded current, a pair of timing relays, means effective when a train enters said section for causing operation of said two relays in sequence whereby the operating times thereof are added to provide a first predetermined time interval during which said code is effective, means operating at the expiration of said first time interval for cutting off said code and for initiating a cycle of operation of said two timing relays to provide a second predetermined time interval of no code, and means controlled by said timing relays effective at the expiration of said second time interval for re-applying code to said section.

'7. In combination with a test section of railway track, a pair of timing relays, means controlled by said timing relays effective when a train enters said section for supplying coded current to the section, said coded current being supplied for a given time interval determined by the sequential operation of said two relays, means effective at the expiration of said time interval for cutting ofi" said code and for initiating a cycle of operation of said two relays to provide a second time interval of no code, and means effective at the expiration of said second time interval for re-applying code to said section.

8. In combination with a test section of railway track, two timing relays one which is normally energized and the other of which is normally deenergized, means efiective when a train enters said section for supplying coded current to the rails thereof and for initiating a cycle of operation of said timing relays whereby said one relay releases and causes pick-up of said other relay, said cycle providing a first predetermined time interval during which code is supplied to said section, means effective when said other timing relay picks up for causing code to be cut oil and for initiating a second cycle of operation during which said other relay releases and causes pick-up of said one relay, said second cycle providing a second predetermined time interval during which code is absent from said section, and means efiective at the expiration of said second time interval for re-applying code to said section.

RALPH R. KEMMERER. 

